Electronic devices which comprise organic, organometallic and/or polymeric semiconductors are being used ever more frequently in commercial products or are just about to be introduced onto the market. Examples which may be mentioned here are organic-based charge-transport materials (for example hole transporters based on triarylamine) in photocopiers and organic or polymeric light-emitting diodes (OLED=organic light-emitting diode or PLED=polymeric light-emitting diode) in display devices. Organic solar cells (O-SCs), organic field-effect transistors (O-FETs), organic thin-film transistors (O-TFTs), organic integrated circuits (O-ICs), organic optical amplifiers and organic laser diodes (O-lasers) are at an advanced stage of development and may achieve major importance in the future.
Many of these electronic or opto-electronic devices have, irrespective of the particular application, the following general layer structure, which can be adapted for the particular application:                (1) substrate,        (2) electrode, which is frequently metallic or inorganic, but may also be built up from organic or polymeric conductive materials,        (3) optionally one or more charge-injection layer(s) or interlayer(s) for compensation of unevenness of the electrode (“planarisation layer”), which is (are) frequently formed from one or more conductive, doped polymer(s),        (4) at least one layer of an organic semiconductor,        (5) optionally one or more further charge-transport or charge-injection or charge-blocking layer(s),        (6) counterelectrode in which the materials mentioned under (2) are employed,        (7) encapsulation.        
The present invention is directed in particular, but not exclusively, to organic light-emitting diodes (OLEDs), which, in the case of the use of polymeric materials, are often also known as polymeric light-emitting diodes (PLEDs). The arrangement described above represents the general structure of an opto-electronic device, where various layers may be combined, meaning that, in the simplest case, an arrangement consists of two electrodes, between which an organic layer is located. In this case, the organic semiconductor layer takes on all functions, including the emission of light. A system of this type is described, for example, in WO 90/13148 A1 on the basis of poly(p-phenylenes).
The polymers for opto-electronic applications which can be used in the organic semiconductor layer mentioned above are generally polymers having a conjugated or partially conjugated main chain, where the polymer backbone itself plays an important role with respect to the opto-electronic properties, side-chain polymers, such as, for example, PVK (poly-N-vinyl-carbazole), in which the functionality is achieved by a transport unit which is chemically bonded to the backbone, or neutral polymers, which merely provide the film-formation properties (as is known of organic photoreceptors, in which hole-transport materials are typically dissolved in polycarbonate). All these approaches are in principle viable and are described in the literature.
Conjugated polymers for opto-electronic applications, such as, for example, polyfluorenes, polyindenofluorenes, polyphenylenes and polyphenylenevinylenes, have proven suitable for OLED applications and organic photovoltaic applications. The lifetime of the devices produced from these polymers has constantly increased over the years, but progress was slower than in the case of “evaporated small molecule” devices (SMOLEDs). The reason for this is attributable to the fact that functionalities necessary in a multilayered SMOLED, such as, for example, hole transport, electron transport, recombination and emission, can be separated into respective layers, whereas all these functionalities are combined in one layer in the partially or fully conjugated polymer. Conjugated polymers are at present the best option of the three mentioned above, since, in particular, stable electron-transport molecules are not readily available and consequently cannot be incorporated easily into a neutral matrix. This transport part is usually taken on by the backbone, but is apparently not as stable as in SMOLEDs. In addition, conjugated units are connected to one another and therefore shift the HOMO-LUMO separation in the direction of lower energies, which limits the available color range for conjugated polymers (a deep blue is virtually impossible in the case of a fully conjugated polymer). Owing to the problems with respect to the limitation of the lifetime and the band separation, the other two approaches appear to be more interesting, since they are more similar to the case of the small molecule. However, random mixing of electron- and hole-transport molecules in a matrix usually results in charge-transfer states, which usually quench the electroluminescence.
On the other hand, side-chain polymers, such as, for example, PVK, have a neutral, PE-like backbone and are therefore prepared either by free-radical, cationic, anionic or coordinative polymerisation. However, it is not simple to control these processes since, in particular, the tolerance with respect to free-radical or charged end groups in OLED devices is rather low (ppm level). In addition, functional units can come quite close since the polymerisation is a random process, meaning that charge-transfer complexes or dimer formation (as is known of PVK) represent(s) a significant hurdle with respect to efficiency and a long life.
In view of the prior art described above, the object of the present invention consisted in providing novel opto-electronically functional oligomers or polymers for opto-electronic applications, in particular for OLED applications, which do not have the above-mentioned disadvantages of known approaches, and an opto-electronic device which comprises the novel, opto-electronically functional oligomers or polymers.
This object is achieved in accordance with the invention by a fluorine-bridged associate according to Claim 1 and an opto-electronic device according to Claim 5. Advantageous refinements and embodiments of the present invention are indicated in the dependent claims.